How does white phosphorus work as a smoke grenade?

From what I gather, white phosphorus is a material that can burned easily in the air and used in weaponry. Playing Spec Ops The Line showed how it can be used as an artillery piece where the white phosphorus can be used to burn people.

Which made me wonder how it can be used as smoke grenade as a screening tactic when it can burn anyone. How is it fired in order to make it a smoke grenade?

I also wonder how white phosphorus can destroy vehicles in Spec Ops?